• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1868-1869
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• 2011

인간의 모션을 센싱해서 로봇을 원격조정함에 있어서 각 관절에 대한 제어명령을 무선으로 전달함으로서 배선의 어려움 등을 없앨 수 있다. 이에 대한 기초 연구로서 DC모터에 대한 원격제어를 Labview를 이용해서 구현하였다. 인간의 움직임은 3축가속도 센서를 사용함으로써 관절의 각도변화를 측정하여 그에 따라 따라 모터의 회전각이 변하도록 하였다 모터의 제어에 있어서는 NI사의 PXI를 사용하였으며 모션센싱부와 PXI와의 데이터 전송은 하는 RS-232 기반의 무선 모듈을 사용하였다. 제어기는 LabView 프로그램으로 작성된 PID제어기를 사용하였다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1992.11a
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• pp.39-40
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• 1992

This paper dealt with the manufacturing of binary alloy catalyst and showed simple electrochemical method for determing catalytic activity of oxygen reduction in acid or alkaline electrolyte. The catalyst was prepared by impregnating transition metal salts on platinum or silver particles adsorbed before on carbon paper substrate. The electrochemical characteristics of the catalysts was investigated with carbon paper electrode or PTFE-boned porous electrode and then cathodic current densities and tafel slopes were compared. As a result, of all binary catalysts utilized in this work, Pt-Fe, Pt-Mo showed better oxygen reduction activity than pure platinum catalyst in acid electrolyte and Ag-Fe, Ag-Pt, and Ag-Ni-Bi-Ti catalyst did than pure silver catalyst in alkaline electrolyte. The current density of Pt-Fe electrode in acid electrolyte was one and half times higher than that of Pt electrode(~500mA/$\textrm{cm}^2$ at 0.7VvsNHE).

• Journal of the Korean Society for Heat Treatment
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• v.27 no.3
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• pp.133-140
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• 2014

Cleavage fracture behaviors were investigated in Ni-Mo-Cr steels with mixed microstructure of lower bainite and martensite. As the size of carbide decreased, the cleavage fracture strength increased, which was independent of the sizes of grain and packet. The measured cleavage fracture strengths were in good agreement with cleavage fracture strengths calculated by Petch model rather than by modified Griffith model in micro-structures with fine carbides, the size of which were small below a few hundred nanometer.

• The Journal of the Korean dental association
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• v.22 no.9 s.184
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• pp.781-792
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• 1984

The purpose of this experiment was to study the effects of laser on a base metal alloy for dental casting. In this study, microhardness, corrosion resistance, wear resistance, interaction behavior of metal-ceramic interface, and bond strength were tested before and after the laser treatment for metal-ceramic alloy. The conclusion arised from this study are as follows: 1. The hardness of lased area was higher than that of unlased area. 2. The corrosion resistance was higher in lased specimen than in unlased specimen. 3. the wear resistance was higher in Iased specimen than in unlased specimen. 4. The EDAX showed that Mo, Si and Al were increased in lased surface but Ni and Cr not increased. 5. The SEM of lased area revealed a typical microstructure. 6. The bond strength of lased specimen was increased in 11.2% than of unlased specimen.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.355-355
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• 2010

We studied the dependence of the performance of schottky barrier metal-oxide-field effect transistors(SB MOSFETs) on the work function of source/drain metals. A strong impact of the various work functions and the light wavelengths on the transistor characteristics is found and explained using experimental data. We used an insulator of a high thickness (100nm) and back gate issues in SOI substrate, subthreshold swing was measured to 300~400[mV/dec] comparing with a ideal subthreshold swing of 60[mV/dec]. Excellent characteristics of Al/Si was demonstrated higher on/off current ratios of ${\sim}10^7$ than others. In addition, extensive photoresponse analysis has been performed using halogen and deuterium light sources(200<$\lambda$<2000nm).

• Journal of Ocean Engineering and Technology
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• v.5 no.1
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• pp.88-96
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• 1991

Fatigue life and retardtion behavior after through-thickness were examined experimentally by using a CT specimen and surface-cracked specimen. The material used was 3% Ni-Cr-Mo steel. The fatigue crack shape before through-thickness is almost semicircular, and the measured aspect ratio is larger than the value obtained by calculation using the K value proposed by Newman-Raju. It is found that the crack growth behavior on the back side after through-ghickness is unique and can be divided into three stages a, b and c. A retardation parameter has been used successfully to predict the growth of cracks in specimen, and in this time, retardation factor is 4.3. By using the crack propagation rule considering on retardation state and the K value proposed by the authors, the remarkable crack growth behavior and the change in crack shape can be evaluated quantitatively.

• Journal of Korea Foundry Society
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• v.9 no.3
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• pp.237-246
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• 1989

This study has been carried out to investigate the difference of rolling life and rolling wear characteristics for various high strength ductile iron castings under unlubricative dry rolling condition by Amsler type wear test with 9.09% sliding ratio. The tensile strength of the castings have been obtained 80, 90 and $100kg.f/mm^2$ as cast-state with pearlitic, bainitic and martensitic matrix structures alloyed with Mo, Cu and Ni. It has been found that the amount of rolling wear is decreased when the tensile strength and hardnees of the castings are increased. The amount of rolling wear is increased, when the maximum compressive stress are increased. The maximum weight loss ratio of rolling wear of the castings are same at the 70000 numbers of revolution with out the maximum compressive stress.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.137-139
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• 2006

In order to establish the optimum hot forming temperature and solution heat treatment temperature for 25% chromium super duplex stainless steel weld, a commercial 25%Cr-10%Ni-4%Mo weld metal for super duplex stainless steel(UNS S32750) with different solution heat treatment conditions at $1100^{\circ}C,\;1050^{\circ}C,\;1025^{\circ}C\;and\;1000^{\circ}C$ for 1.5 hours has been investigated by means of optical metallography, and estimated mechanical properties. It is found that exposure to elevated temperatures at $1050^{\circ}C,\;1025^{\circ}C\;and\;1000^{\circ}C$ except $1100^{\circ}C$ brings partial decomposition of ferrite to austenite and sigma phase, which deteriorates their properties and heat treatment at $1100^{\circ}C$ shows acceptable mechanical properties.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.688-691
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• 1997

Good quality superconducting $YBa_2Cu_30_{7-{\delta}}$(YBCO) thin films were grown on Hastelloy (Ni-Cr-Mo alloys) with yttria-stabilized zirconia(YSZ) buffer layers by in situ pulsed laser deposition in a multi-target processing chamber. Generally, Hastelloy exhibits excellent resistance to corrosion, fatigue, thermal shock, impact, and erosion. However, it is difficult to make films on flexible metallic substrates due to interdiffusion problems between metallic substrates and superconducting overlayers. To overcome this difficulty, it is necessary to use YSZ buffer layer since it will not only limit the interdiffusion process but also minimize the surface microcrack formation due to smaller mismatch between the film and the substrate. In order to enhance the crystallinity of YBCO films on metallic substrates, YSZ buffer layers were grown at various temperatures different from the deposition temperature of YBCO films. On YSZ buffer layer grown at higher temperature than that for depositing YBCO film, the YBCO thin film was found to be textured with c-axis orientation by x-ray diffraction and had a zero-resistance critical temperature of about 85K.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.185-189
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• 1999

There has been a considerable attention in Invar alloys because of its low thermal expansion property. A low thermal expansion property of Invar alloys, lower than 10-6 near the room temperature, is attractive for precision machine tools. However, the expansion property of Invar alloys is limited below about 520。K, and mechanical properties are relatively low to apply to machine tools. In order to improve mechanical properties in this alloy, Ti alloy element was added to an invar alloy. Microstructure changes and optimum heat-treatment conditions according to Ti addition were discussed in the Ni38-Mo2-Crl-Fe Invar alloy.